Catalan nationalists have mobilised and were out on the streets all last night

Crowds supporting the Catalan's nationalists in Barcelona last night yelled for national security forces to get out of the region, branding them "occupation forces" and raising their middle fingers at a police helicopter circling overhead.

Tens of thousands surged through the streets of the northeastern region against action by the police who tried to disrupt Sunday's vote by firing rubber bullets and charging into crowds with truncheons.

When asked what he would do if the Spanish government were to intervene and take control of Catalonia's government, Mr Puigdemont said it would be "an error which changes everything".

Catalan's bid for separation is considered Spain's worst political crisis since an attempted military coup in 1981, which was defused by the current king's father, King Juan Carlos I.

Locals talk at a restaurant as King Felipe makes a televised address to the nation

King Felipe VI made the rare television appearance in the evening and accused authorities in Catalonia of deliberately bending the law and undermining coexistence, adding that the Spanish state has a duty to ensure unity and constitutional order in the country.

"Today, Catalan society is fractured," Felipe said in his address to the nation, referring to the political crisis as "very serious moments for our democratic life".